RM4SCC

Values ​​of the bars

Sample code

Distorted print image

RM4SCC ( Royal Mail 4 State Customer Code ) is a bar code developed by Royal Mail in the UK .

history

The RM4SCC was developed in Great Britain by the Royal Mail, but is now also used in other countries ( Switzerland , Austria , Denmark , Australia ), which however use different definitions of the characters or structure the code differently. The Universal Postal Union has also issued corresponding specifications.

Structure and properties

Each individual bar takes an (engl. Four states 4 state ) on, thus encodes two bits. The four possible states are shown in the examples on the right. Four bars each form a group of eight bits or one byte and encode one character.

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The arrangement of the printed characters is defined in both directions; This means that the code must correspond to the specifications both in the direction of transport and vice versa. In practice this means that at least sharp vertical lines have to be printed. In addition, the aspect ratios are specified for most codes.

At very high speeds (for example, 3.5 m / s for letter sorting) it is not possible to print directly within the tolerances using an inkjet printer, for example . As a rule, lines are distorted and curved, which is due to the short flight time between the creation of a point and the impact on the rapidly moving printing surface. This means that the tolerances for 2-dimensional codes are usually no longer adhered to or the codes have to become too small (data volume and reading reliability low).

The RM4SCC is particularly suitable for very high speeds with direct printing, as it tolerates distortions as far as possible. The example opposite shows a distorted code. It is still easy to read, as the tracker is present in every line. Reading technology uses this as a trigger to decide whether something has been printed above or below. It becomes problematic if the individual lines run into each other, as the tracker clock is then difficult to find. Codes running at an angle are also much more difficult to read, since the center line can only then be found from the overall image with the tracker. The specifications of the code therefore define appropriate tolerances.

Individual evidence

1. ↑ UPU Technical Standards: S18 - ID-tagging of letter mail items